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  <title>JS基础</title>
  <script type="text/javascript">
    var a, b, sum;
    var a = 5;
    var b = 100 % 7;
    sum = a > b && a * b > 0;
    document.write("我认为 a 的值是:" + a + " b的值是:" + b + "sum 的值是:" + (a + b) + "<br/>");
    document.write("答案是,第一轮计算后，a 为：" + a + ";b为：" + b + ";第一次计算sum为：" + sum + "<br/>");

    sum = ((++a) + 3) / (2 - (--b)) * 3;
    document.write("再一次计算后，我认为 a 的值是:" + 6 + " b的值是:" + 1 + "sum 的值是:" + 27 + "<br/>");
    document.write("答案是，第二轮计算后，a 为：" + a + ";b为：" + b + ";第二次计算sum为：" + sum + ",sum的类型也发生变化了。");

  </script>
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<body>
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